Field of the Invention
The invention relates to shotguns.
Prior Art
The shots of a shotgun's charge, immediately after leaving the barrel, form a bunch cluster, the diameter of which expands as its distance from the shotgun increases. From a certain point and after that, the diameter of this bunch cluster increases so that within the shot pattern empty spaces are formed, such that the shot charge is no longer effective as the target, when these empty spaces become larger than that, can no longer be hit.
For this reason, at the last before the exit front part of the internal of shotgun barrels there is a constriction, i.e. reduction of the internal diameter in the muzzle area in relation to the rest of the barrel bore, in order to tighten the shot charge so that the shot pellets maintain the effective density of their pattern without gaps etc. at a longer distance from the muzzle than the one at which they would had lost it due to significant spread if there was no the constriction at the exit. This constriction varies depending on the distance at which is sought to be achieved the most effective in its density shot pattern diameter, from negative to small for shots at short distances, moderate for shots at medium distances and great for shots at long distances, with all intermediate gradations according to the intended use of each shotgun.
In recent decades, the part of the interior of the barrels at which there is the constriction is interchangeable, ie before the exit of the barrel there is internally a placement slot, at which is placed interchangeable cylindrical tube with fixation screw thread, which has internally the at each time desired by the user of the weapon constriction.
During the phase of detonation, the shot charge is accelerated within a few milliseconds from zero to hundreds of meters per second, with the result, in its course through the barrel bore, a number of shot pellets, due to the high pressure which develops between them, to undergo cold type welding and form aggregates consisting of 2 or more shot pellets. These aggregates, as they do not have spherical shape, in the course of the shot charge in the air after its exit from the barrel, are diverted from the desired path to the target, thereby reducing the effectiveness of the shot. Furthermore, they cause diversion to other nearby them shot pellets, thus worsening even further the reduction of the effectiveness of the shot as they cause bad shot pellet distribution within the diameter of their pattern.